We have had one of those yellow plastic Hozelock 17 hole Aquastorm Sprinker
for a couple of years. It's the type with the curved aluminium tube that
slowly rotates in one direction and then the other direction.

When starting up, it stops moving after a couple of times. I could cut into
the side of it to lubricate any of the moving parts; if this was a feasible
option to get it working properly again.

But I dont know whether the actual 'housing' is pressurised with the water
in it in which case it would just jigger the whole thing for ever.

Grateful for any advice please to get it going.